1. Field of the Invention
This invention relates to a chemical assay system, and more particularly to a chemical assay system in which material to be assayed is caused to act on an assay slide bearing thereon one or more reagent layers and incubated for a predetermined time, and then coloration (extent of dye formation) in the assay slide is optically measured and analyzed for qualitative and/or quantitative determination of a particular component or particular components in the material.
2. Description of the Prior Art
Qualitative and/or quantitative determination of a particular chemical component in a liquid sample is widely used in various industrial fields. Especially, in the fields of biochemistry and clinical medicine, quantitative determination of a particular chemical component or particulate substance in body fluids such as blood or urine is extremely important.
Recently, there has been put into practice a dry type chemical assay slide by which a particular chemical component or material component in a liquid sample can be determined by depositing a droplet of the liquid sample on the slide. Japanese Patent Publication No. 53(1978)-21677, Japanese Unexamined Patent Publication No. 55(1980)-164356, for example, are referred to. By using such chemical assay slides, liquid samples can be assayed more easily and more quickly in comparison to the conventional wet analyzing process, and accordingly, the chemical assay slide is conveniently used in medical facilities, laboratories and the like where a large number of samples must be assayed.
When a liquid sample is assayed using the chemical assay slide, a measured quantity of the liquid sample is deposited on the slide and the slide is held in an incubator for a predetermined time at a constant temperature to permit reaction to cause coloration, and then light including a wavelength selected previously depending on the components of the liquid sample and the reagents contained in the reagent layers on the slide is projected onto the slide to measure the reflection density thereof.
In case where a large number of samples are assayed, automatic and continuous assay is preferred. Therefore, there have been proposed various chemical assay systems in which analysis of samples can be automatically and continuously effected using the dry type chemical assay slides described above.
For example, in the system disclosed in Japanese Unexamined Patent Publication No. 56(1981)-77746, a plurality of the chemical assay slides are sandwiched between a pair of rotatable disks at regular intervals in a circumferential direction of the disks and held at an elevated constant temperature for incubation by heaters provided on the disks, and after incubation for a predetermined time, the rotatable disks are rotated to successively oppose the slides to a probe disposed below the disks. The probe projects irradiating light onto each slide opposed thereto and receives reflected light through an opening formed in the lower disk. Though being advantageous in view of the efficiency in analyzing numerous samples, the system is disadvantageous in that a complicated disk rotating system including a control system is required which adds to the manufacturing cost and the size of the overall system.
In the system disclosed in Japanese Unexamined Patent Publication No. 58(1983)-21566, a U-shaped transfer path is formed in an incubator, each of a plurality of the chemical assay slides is supported by a carrier of a predetermined shape and is successively transferred along the transfer path, and each chemical assay slide is subjected to measurement of the reflected light density by a probe disposed along the transfer path after incubation for a predetermined time during transfer along the transfer path. The system is also advantageous with respect to the efficiency in effecting analysis of a plurality of samples, but is disadvantageous in that a mechanism for transferring the carriers for supporting the slides along the transfer path is required which adds to the manufacturing cost and the size of the overall system. Further, the system is disadvantageous in that it is not suitable for measuring the reflected light density a plurality of times in order to detect the rate of change of the optical density.
Further, there has been known a chemical assay system in which a plurality of chemical assay slides are stacked in an incubator, and after a predetermined time, the slides are successively taken out from the lowermost one to be subjected to measurement of the reflected light density. This system is advantageous in that since the slides are stacked in the incubator, the incubator may be relatively small in size but involves a problem that gas formed by the reaction occuring in one slide during incubation affects the reaction occuring in the other slides, lowering the accuracy of assay. Further, this system is not suitable for measuring the reflected light density a plurality of times in order to detect the rate of change of the optical density since the slides must be successively taken out from the incubator when the reflected light density is measured. Accordingly, it is difficult to measure the reflected light density during incubation.